Protein-water interactions will be studied using measurements of protein heat capacities and optical properties as a function of water content. Heat capacity measurements on model compounds will be performed to complement literature data and furnish the background information needed to interpret the protein results. Changes in protein conformation at low water content will be assessed. The effect of change in solvent composition on the lysozyme-catalyzed reaction will be measured in order to examine the participation of solvent in equilibrium and catalytic processes.